The present invention relates to a microactuator for fine positioning of a transducing head over a selected track of a rotatable disc of a disc drive, and more particularly to a piezoelectric microactuator fabricated at the wafer level by conventional thin film techniques used to manufacture the transducing head on the slider.
The density, or radial spacing, between concentric data tracks on magnetic discs continues to increase, requiring greater precision in head positioning. Conventional disc drives accomplish head positioning by operating an actuator arm with a large scale motor, such as a voice coil motor, to position a head on a gimbal at the end of the actuator arm. The large scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism is necessary to accommodate the more densely spaced tracks.
One promising design for high resolution head positioning employs a high resolution microactuator in addition to the conventional low resolution actuator, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning, including piezoelectric, electromagnetic, electrostatic, capacitive, fluidic, and thermal actuators. Various locations for the microactuator have been suggested, one such microactuator being at the interface between the gimbal and the slider, as described in U.S. patent application Ser. No. 08/852,087, filed May 7, 1997 now U.S. Pat. No. 5,898,541 by Z. Boutaghou and L. Berg, which is hereby incorporated herein by reference in its entirety. However, many previous microactuator designs were directed to microactuators fabricated independently of the slider which had to be subsequently attached to the slider. Consequently, the microactuator could not be fabricated during the same thin film wafer processing for manufacturing the slider and transducing head, and additional tooling and assembly steps were required to attach the microactuator to the slider. As a result, the complexity of the manufacturing process was increased and additional fabrication steps, separate from existing manufacturing techniques, were required, making these microactuator designs prohibitively expensive and inefficient to produce.
There is a need for a microactuator design that provides high resolution head positioning and that can be manufactured efficiently and inexpensively. More particularly, there is a need for a microactuator design that can be fabricated onto the slider using existing wafer processing techniques.